Some people have expressed doubts about what a microphone can pick up.
There are many types of microphone, and in my work I regularly use Pressure Zone (or "Boundary Effect") Mics, as well as standard "Omni-directional" Mics.
These are low cost and freely available, and do indeed pick up everything in a room clearly, and almost equally; thus they are superb for conferences, music and stage work. I do not know what type of mic is used in the flight deck, but miniature versions of all these mics are available.
Even with my fairly basic music/audio software I can enhance and process what the mic has picked up.
I see no reason to cast doubt on what was heard.